God in Proof: The Story of a Search from the Ancients to the Internet

Review of Nathan Schneider, God in Proof: The Story of a Search from the Ancients to the Internet. University of California Press, 2013. 254 pages.

By William Converse

Nathan Schneider is an engaging young American writer on religion and reason whose work has appeared in Harper’s, the New York Times, and the Guardian.

This is a personal odyssey as well as a survey of the classical arguments for the existence of God, from ancient India and classical Greece to the twenty-first century and the Internet.

Schneider starts with a cautionary tale. In Laurence Cossé’s sardonic novel, Le Coin du Voile (English title: A Corner of the Veil), an envelope is delivered to la Compagne casuiste in Paris, containing what purports to be an irrefutable proof of the existence of God. When experts concur, the authorities become dismayed. Remitted to Rome, la prevue is suppressed.

For Schneider premises and definitions are very important. So also is “proof”:

“Some will object to talking about proof at all. They’ll say that any absolute or mathematical proof for God sets the bar too high, or too low. Instead, call it argument, or demonstration—or call it faith. But proof fits the story I’m trying to tell like no other word.” (Author’s italics)

The word “proof” comes from the Latin verb probare, to test, to try or prove (as in probate or probative). He cites an OED definition: “That which makes good or proves a statement; evidence sufficient (or contributing) to establish a fact or produce belief in the certainty of something.”

Schneider begins his overview of the proofs for the existence of God with Pythagoras and Greek mathematics (geometry) before discussing Socrates, Plato and Aristotle. His treatment of Plotinus and Augustine of Hippo is excellent. The chapter on the medieval Islamic and Jewish philosophers, Avicenna (Ibn Sina), Averroës (Ibn Rushd) and Moses Maimonides is especially interesting. He discusses Anselm of Canterbury, Thomas Aquinas and John Duns Scotus. He then turns his attention to proofs of early modern European philosophers: René Descartes, Blaise Pascal, Benedict de Spinoza, Gottfried Leibniz, followed by the criticisms of David Hume and Immanuel Kant.

The traditional proofs for the existence of God were formulated by Thomas Aquinas in his Summa Theologiae. Known as “the Five Ways,” they are: (1) the arguments from motion; (2) the argument from causality; (3) the argument from contingency; (4) the argument from degrees of perfection; and (5) the argument from design or purpose in nature. In the 18th century Immanuel Kant reduced them to three categories of proof: the cosmological, the teleological, and the ontological. Using the terminology of the German Enlightenment philosopher, Christian Wolff, Kant called them “physico-theological” because they attempt to prove the existence of God from observed facts about the world. In the 19th century, Hegel, in Lectures on the Proofs of the Existence of God, explained how they reflect distinct world-views: the cosmological argument, the primitive religion of nature; the teleological argument, the ascendancy of human reason; while the ontological argument caps both: “The explication for the proofs of God’s existence is the explication of religion itself.” Hegel’s own proof is a dialectical synthesis of the older proofs:

“The three proofs, each composed of dialectics in themselves, fold together into an even grander dialectical scheme. For this, Hegel summons the ancient distinction between a priori and a posteriori proofs, the distinction that separated Platonism from Aristotle, Anselm from Aquinas, and the rationalists from the empiricists. For him, each represents an opposing tendency: the a priori takes us from God to being, the a posteriori from being to God. The ontological proof fits into the first, while the cosmological and teleological proofs, beginning with the world and leading to God, make up the second. But these types need each other, and they satisfy what the other is missing: the concept of God in one and, in the second, the nature of creation. Their dialectical synthesis delivers the reality of God’s existence—though even to speak of ‘existence,’ he wrote, ‘is too low for the Absolute Idea, and unworthy of God.’ No, God’s existence is not a mere predicate. It’s so much more.”

In the early 20th century the Logical Positivists and analytic philosophers were convinced that they had finally disposed of these arguments. Metaphysical statements were held to be either invalid or meaningless; they were “unintelligible.” In Language, Truth, and Logic (1936), A.J. Ayer asserted: “To say that ‘God exists’ is to make a metaphysical utterance which cannot be either true or false.” In 1950, the British analytic philosopher and avowed atheist Antony Flew read a singular paper to the Oxford Socratic Club, hosted by C.S. Lewis, entitled “Theism and Falsification.” Towards the end of his life, however, Flew changed his mind and embraced Aristotle’s God.

Schneider gives an Islamic version of the cosmological argument, a variant of Aristotle’s argument for the Prime Mover in Book 12 of the Metaphysics. It is called the Kalām cosmological argument because it was formulated by Islamic philosophers belonging to the Kalām tradition (Kalām is the Arabic word for discourse or disputation). It is one of a set of Muslim proofs for the existence of God. The American philosopher of religion William Lane Craig popularized it in his book, The Kalām Cosmological Argument (1979/2000). Craig has devoted much of his career to promoting the argument in lectures and on YouTube. The proof is reproduced on page 30.

The ontological argument was first developed by Anselm of Canterbury. This is an analytic, a priori argument, based on the concept of God as a perfect being. No one yet has satisfactorily explained how it works. Bertrand Russell attempted by logical analysis to show that it was not a valid argument, though he initially accepted the argument as sound. Richard Dawkins dismisses it as “logomachist trickery.”

Anselm’s contemporary, Gaunilo of Marmoutiers, was the first to criticize the proof. Anselm replied that the idea of God as a perfect being entails necessary existence. Thomas Aquinas rejected it on the grounds that we cannot know God’s essence. Most medieval theologians followed Aquinas. In the 17th century, Descartes presented several variants of the ontological proof that Leibniz augmented.

In the 20th century, the revival of interest in modal logic (the branch of logic dealing with possibility and necessity) emboldened several philosophers, including the Austrian mathematician and philosopher Kurt Gödel and the American analytic philosopher Alvin Plantinga, to construct modal variants of the ontological argument. An autograph of Gödel’s proof appears on page 79.

The 13th century Franciscan philosopher John Duns Scotus, known as the “Subtle Doctor,” achieved a brilliant synthesis of Anselm and Aquinas with an elegant and intricate proof for the existence of God that combined elements of Aquinas’s “Five Ways” with Franciscan mysticism. In the 16th century, this style of reasoning fell into disfavour. “Duns” then morphed into “dunce.”

The young Thomas Merton enthused over Scotus’s argument: “For accuracy and depth and scope, this is the most perfect and complete and thorough proof for the existence of God that has ever been worked out by any man.”

Schneider clearly shares Merton’s enthusiasm:

“This Scotus synthesis was an epic in the genre of proof, but Duns Scotus died young and was never made a saint like his predecessors. His scholastic contrivance soon became a paragon of what more modern thinkers would be eager to set aside. Its intricacy and breadth, however, say something true about what it takes to believe fully and deeply: it requires combining both Anselm and Aquinas, uniting the inward with the outward. Assent, like this, is a convergence—a meeting of circumstances, choices, and the best of one’s knowledge. It is complicated. But, then, when it happens, it’s also simple. It just is. One’s assent becomes yet another fact upon which everything else depends.”

Schneider does not reproduce Scotus’s proof but it can be found at the Stanford University Encyclopedia of Philosophy website.

There is a cameo of the radical medieval philosopher, Siger of Brabant, a rival of Aquinas at the University of Paris. Condemned for propounding the doctrine of “double truth,” the notion that one and the same statement can be true in philosophy and false in theology, Siger went to Italy to appeal his condemnation at the papal court. At Orvieto he was stabbed to death with a pen by his secretary. In the Divine Comedy Dante places Siger next to Aquinas in Canto X of the Paradiso.

Schneider speculates why philosophers have engaged in this peculiarly male pursuit. Most were already believers. Many were mathematicians or logicians. For Augustine and Anselm it was a form of meditation. For Spinoza and Hegel, it underpinned their systems. Wittgenstein opined that it gave believers “an intellectual analysis and foundation” for their beliefs:

“The search for proofs of God’s existence is its own genre, winding through history and sprouting capricious branches. Like any genre, from impressionist painting to romantic novels, proof has never spoken for any whole society. It’s rarely anyone’s sole occupation, but still it has occupied some of history’s most brilliant men.”

Schneider is skeptical about recent arguments based on quantum physics, probability or multiverse theory: “The metaphysics of multiverses, unfortunately, isn’t much more conclusive than the physics.” This notwithstanding, there is in the United States today a veritable proof industry. Its goal is to establish the existence of God as an incontrovertible scientific fact. Absolute certainty is the goal.

In the end these arguments fall short. They do not attain the God of the Abrahamic religions, but lead instead to a First Cause or Necessary Being, what Pascal termed “the God of the savants.” Kierkegaard compared them to tumbler dolls, “these little Cartesian dolls.” John Henry Newman called them “paper arguments.” God’s existence does not depend on syllogisms or equations; God is not a placeholder.

For Schneider, the idea of God surpasses all human ideas and concepts:

“The idea of God, after it first became lodged in me, and once I even partly entertained it, began to take on a life of his own. This process started through other people, but the idea transcended even them. As Anselm replied to Gaunilo, there’s something special about the one most perfect idea, something that applies to no other. You might be able to grasp a humbler notion enough to refute it. But this necessary and infinite necessary being is more elusive, while being also more fully present, than anything else we know. No refutation can suffice. It’s too big. Its possibilities never stop exceeding what we might happen to rule out. This God exceeds what we think about it, and what we think we know about it. It even exceeds those of us who can’t believe in it anymore, and those who never did.”

Born in 1986, Schneider is a millennial. He grew up in a mostly secular milieu, “with trace amounts of Judaism” from his father’s side. His mother was drawn to Eastern mysticism and his writing reflects a mystical bent. His interest in the proofs started when he was a teenager. Brief stays at Holy Cross Abbey, Berryville, Virginia, and Gethsemani Abbey, Kentucky, where Thomas Merton once was a monk, proved formative. At college he became a Roman Catholic. Like Jack Kerouac, he went “on the road” and traveled across the U.S. A voracious reader, Schneider is at home with the Bhagavad Gita, the Talmud, and the Qur’an. God in Proof evidences his extensive reading: Augustine’s Concerning Faith of Things Not Seen, Spinoza’s Ethics, Newman’s Grammar of Assent and Wittgenstein’s posthumous On Certainty.

God in Proof is a fascinating book, written in an informal style, free of technical jargon. The text is illustrated with whimsical line drawings. There is no index but the tables of philosophers and proofs are cross-referenced with page numbers. I noted only one omission and one error: Schneider does not adduce Dostoevsky’s argument against the existence of God from evil in Book V, Pro and Contra, of The Brothers Karamazov; he incorrectly describes John Calvin as “the Swiss Reformer.” Jean Calvin was French. This said, I strongly recommend God in Proof.